1. Field of the Invention
The present invention relates to a device and a method for detecting the existence or the concentration of biomolecules using a field effect transistor.
2. Description of the Prior Art
A transistor-based biosensor is a type of detection device containing transistors therein, which detects biomolecules with electric signals. The transistor-based biosensor is a sensor fabricated using a semiconductor process. It has advantages in that the conversion of the electric signals is fast, and the transistor-based biosensor is relatively easy to dispose on an integrated circuit (“IC”) or a microelectromechanical system (“MEMS”).
Among transistor-based biosensors, a field effect transistor (“FET”) based biosensor is the representative device for measuring biological reactions. In the case of such an FET based biosensor, final products are usually compact detectors suitable for lab-on-a-chip devices or point-of-care products. Conventional FET-based biosensors measure surface charge density, commonly present within a Debye length, and measure electric signals from biomolecules adsorbed on the gate surface. Therefore, in order to use such FET-based biosensors, the biomolecules are essentially fixed to the gate surface of the FET.